Best Free Color Picker for Linux

Best Free Desktop Search Utility for Linux

Recoll, an open source program and a powerful tool allows you to search instantly most common document types, emails and their attachments after indexing your home directory by default. You can configure additional areas for indexing and install supporting packages to include file types that are not indexed natively by the tool as well.

Best Free Font Manager for Linux

Fontmatrix is the largest and most complex application and runs on a wider range of platforms with more high-end features. Some of these features are not available in any of other programs.

You can activate fonts in tagged groups, view many sample texts in many languages, classify fonts using PANOSE, view and compare glyphs, find a font from a raster, extract fonts from PDF files, and test layouts in a free-form playground. (Review)

Font Manager allows you to easily manage fonts installed in your Linux system. You can preview and compare installed fonts, activate and de-activate installed fonts, install new fonts or remove existing fonts, group fonts into collections and export them to an archive for backup and sharing.

Best Free Grub Customizer for Linux

Grub Customizer, a graphical user interface to re-arrange, rename or hide boot menu entries, set a default operating system to boot on a multi-boot device, customize the appearance as well as adjust other settings of Grub (GRand Unified Bootloader).

Best Free Program Launcher for Linux

Launchy, a top product in the keyword search class, easy to understand, simple to configure, extend and use. It's open source and has a really small memory footprint. You can use it not only to launch applications, but also run your media player with a specific MP3 file, have your browser open on a specific bookmark and more. (Review)

GNOME Do, type and search the items on your computer or on the web and the program helps you perform the tasks directly and quickly with suggested actions to take. A large set of official and community plugins are available for making the program more powerful with even more task varieties.

Cairo-Dock, a pretty and light program allows you to launch your applications right away from the dock on your desktop, supporting useful features such as multi-docks, applets, themes and various settings to change the appearance and behavior of the program to your liking.

Best Free Screen Capture for Linux

Shutter is like a swiss army knife for all screen capture tasks in Linux. It works better than Gnome-screenshot and KDE's KSnapshot.

You can use this program to capture desktop, window, child window and rectangular area, with many plugins for resize and special effects, delay capture, activate/deactivate window border and cursor, inbuilt drawing tools, linked to external editor and auto save. (Review)

Best Free Screen Session Recorder for Linux

recordMyDesktop, an easy-to-use and effective recorder to make screen recordings into free Ogg video format. It also offers the ability to record audio through ALSA mixer or other options. The frontend program gtk-recordMyDesktop and the ALSA mixer can be downloaded from some depositories including Ubuntu Software Center.

Best Free System Information Utility for Linux

I-Nex, similar to the application CPU-Z for Windows, gathers and displays information for hardware components on your system, including CPU, GPU, Motherboard, Audio, Drives, System, Linux Kernel, Memory, Network and USB devices plugged in. It also allows you to generate a report of the info and take a screenshot of the I-Nex window.

PySDM, a Storage Device Manager allowing for full customization of hard disk mountpoints and creation of rules for dynamic configuration of storage devices. See also Auto Mount Drives at System Startup.

Best Free Wallpaper Changer for Linux

The program supports features such as time intervals, selecting images from local folders or online resources, displaying images' EXIF data in system tray tool-tip, saving downloaded photos and run-time folder change detection. (Review)

Variety is an open-source wallpaper changer packed with a variety of great features, such as automatically fetching wallpapers from your favorite folders or online sources, applying filters to the displayed wallpapers, matching wallpapers with color and size, showing random wise quotes and a configurable digital clock on the desktop. You can set Variety to change wallpaper on start or every fixed time interval.

DesktopNova, change your desktop wallpapers automatically based on a list of image files you've added, or even better, based on a list of folders and subfolders containing your favorite images. With this application, you can set wallpapers to change upon each login session or at every fixed time interval to your liking.

Webilder, rotate your wallpapers automatically from your collection at a time interval you set, and download new photos from Flickr or Webshots to your collection using tags or image type. Settings are available for different desktop environments such as GNOME3, GNOME, KDE and Xfce.

Best Free Windows API for Linux

Wine allows for running Windows applications on Linux and other operating systems, but without a copy of Windows. It's still under active development and not every program works yet.

"... The SPICE project aims to provide a complete open source solution for remote access to virtual machines in a seamless way so you can play videos, record audio, share usb devices and share folders without complications ...":
https://spice-space.org/

"... Noobs Terminal is a single-command installer that incorporates some of the wonderful terminal programs, packages, and configurations that are commonly installed together ...": https://noobs-term.com/

"... Software projects are displayed by Gource as an animated tree with the root directory of the project at its centre. Directories appear as branches with files as leaves ...": http://gource.io/

"... Pext stands for Python-based extendable tool. It is built using Python 3 and Qt5 QML and has its behaviour decided by modules. Pext provides a simple window with a search bar, allowing modules to define what data is shown and how it is manipulated ...":
https://github.com/Pext/Pext

"... fstransform is a tool to change a file-system from one format to another, for example from jfs/xfs/reiser to ext2/ext3/ext4, in-place and without the need for backup ..."::
https://github.com/cosmos72/fstransform

"... Cronopete is a Linux clone of Time Machine, the backup utility for Mac from Apple. It aims to mimic it as closely as possible ...":
http://www.rastersoft.com/programas/cronopete.html
"... Multipackager is a program that aims to simplify the creation of packages for linux distributions. To do so, it automatizes the creation of virtual machines with specific distributions, versions and architectures, and the compilation and packaging process for each one, both for binary and Python projects. It allows to create packages for i386 and amd64 architectures, for any available version of Debian, Ubuntu, Fedora and Arch ...":
http://www.rastersoft.com/programas/multipackager.html

"... Symphytum is a personal database software for everyone who desires to manage and organize data in an easy and intuitive way, without having to study complex database languages and software user interfaces ...":

"... Cmdtypist is a programmer oriented typing tutor ... designed to work on the gnome-terminal, xterm and uxterm and other consoles. It consists true programming lessons, so the user can type and learn at the same time ...":
https://github.com/Noslac/cmdtypist

"... Porg is a program to aid management of software packages installed from source code. After the installation of such packages, one is usually left with having no idea of what it was installed and where it all went, making it difficult to uninstall the package in the future. Porg was written to solve this problem in a quite simple fashion...":
http://porg.sourceforge.net